U.S. patent application number 11/992882 was filed with the patent office on 2009-09-17 for biodiagnosis apparatus.
Invention is credited to Ryo Machida.
Application Number | 20090234234 11/992882 |
Document ID | / |
Family ID | 37942772 |
Filed Date | 2009-09-17 |
United States Patent
Application |
20090234234 |
Kind Code |
A1 |
Machida; Ryo |
September 17, 2009 |
Biodiagnosis Apparatus
Abstract
The invention provides a biodiagnosis apparatus capable of
observing a reflection image of a site other than a fluorescent
site through excitation light taken in an observation system so
that fluorescence observation can be implemented in good enough
color contrast. The apparatus a light source (21), a light source
optical system (22), a light transfer system (3) for guiding
illumination light from the light source (21) to the living body,
an excitation light filter (24) interposed between the light source
(21) and the light transfer system (3), an image transfer system
for guiding light from the living body to an image plane, and an
excitation cut filter (11) located in said image transfer system.
The spectral characteristics of illumination light transmitting
through the excitation filter (24) and the transmittance
characteristics of the excitation cut filter (11) have an
overlapping portion. Upon observation of a subject under the
biodiagnosis apparatus, the spectral characteristics of a site of
the image plane other than a fluorescent site satisfy the following
condition:
0.005.ltoreq.I(.lamda..sub.p+.DELTA.)/I(.lamda..sub.p).ltoreq.0.5
provided that 40.ltoreq..DELTA..ltoreq.80 nm, where .lamda..sub.p
is the wavelength (nm) at which the spectral intensity reaches a
maximum, and I(.lamda..sub.p) is indicative of the then spectral
intensity.
Inventors: |
Machida; Ryo; (Tokyo,
JP) |
Correspondence
Address: |
KENYON & KENYON LLP
ONE BROADWAY
NEW YORK
NY
10004
US
|
Family ID: |
37942772 |
Appl. No.: |
11/992882 |
Filed: |
October 4, 2006 |
PCT Filed: |
October 4, 2006 |
PCT NO: |
PCT/JP2006/320234 |
371 Date: |
March 27, 2008 |
Current U.S.
Class: |
600/476 |
Current CPC
Class: |
A61B 5/0084 20130101;
G01N 21/6486 20130101; G01N 21/645 20130101; G01N 2021/6471
20130101; A61B 5/0086 20130101; A61B 5/0071 20130101 |
Class at
Publication: |
600/476 |
International
Class: |
A61B 6/00 20060101
A61B006/00 |
Foreign Application Data
Date |
Code |
Application Number |
Oct 12, 2005 |
JP |
2005-297367 |
Claims
1. A biodiagnosis apparatus harnessing fluorescent reactions of a
living body tissue, which comprises a light source, a light source
optical system, a light transfer system for guiding illumination
light from said light source to the living body, an excitation
light filter interposed between said light source and said light
transfer system, an image transfer system for guiding light from
the living body to an image plane, and an excitation cut filter
located in said image transfer system, and in which spectral
characteristics of illumination light transmitting through said
excitation light filter and transmittance characteristics of said
excitation cut filter have an overlapping portion, characterized in
that: upon observation of a subject under said bio-diagnosis
apparatus, spectral characteristics of a site of the image plane
other than a fluorescent site satisfy the following condition (1):
0.005.ltoreq.I(.lamda..sub.p+.DELTA.)/I(.lamda..sub.p).ltoreq.0.5
(1) provided that 40.ltoreq..DELTA..ltoreq.80 nm, where
.lamda..sub.p is a wavelength (nm) at which spectral intensity
reaches a maximum, and I(.lamda..sub.p) is indicative of the then
spectral intensity.
2. A biodiagnosis apparatus harnessing fluorescent reactions of a
living body tissue, which comprises a light source, a light source
optical system, a light transfer system for guiding illumination
light from said light source to the living body, an excitation
light filter interposed between said light source and said light
transfer system, an image transfer system for guiding light from
the living body to an image plane, and an excitation cut filter
located in said image transfer system, and in which spectral
characteristics of illumination light transmitting through said
excitation light filter and transmittance characteristics of said
excitation cut filter have an overlapping portion, characterized in
that: chromaticity coordinates (x, y) for light after transmitting
through said excitation cut filter satisfies the following
condition (2): 0.16.ltoreq.x.ltoreq.0.21, 0.04.ltoreq.y.ltoreq.0.23
(2)
3. A biodiagnosis apparatus harnessing fluorescent reactions of a
living body tissue, which comprises a light source, a light source
optical system, a light transfer system for guiding illumination
light from said light source to the living body, an excitation
light filter interposed between said light source and said light
transfer system, an image transfer system for guiding light from
the living body to an image plane, and an excitation cut filter
located in said image transfer system, and in which said light
source filter comprises a first transmissive area containing a
fluorescence excitation wavelength and a second transmissive area,
with transmittance characteristics of said excitation cut filter
including said second transmissive area of said light source
filter, characterized in that: upon observation of a subject under
said bio-diagnosis apparatus, spectral characteristics of a site of
the image plane other than a fluorescent site satisfy the following
condition (1):
0.005.ltoreq.I(.lamda..sub.p+.DELTA.)/I(.lamda..sub.p).ltoreq.0.5
(1) provided that 40.ltoreq..DELTA..ltoreq.80 nm, where
.lamda..sub.p is a wavelength (nm) at which spectral intensity
reaches a maximum, and I(.lamda..sub.p) is indicative of the then
spectral intensity.
4. The biodiagnosis apparatus according to claim 3, characterized
in that said light source comprises a first light source in
alignment with said first transmissive area and a second light
source filter in alignment with said second transmissive area, and
is designed to direct sequentially to the subject light
transmitting through said first light source filter and light
transmitting through said second light source filter.
Description
TECHNICAL ART
[0001] The present invention relates generally to a bio-diagnosis
apparatus, and more particularly to a bio-diagnosis apparatus that
lends itself to fluorescent observation and diagnosis of tumors or
the like in a living body in general, and the bladder in
particular.
BACKGROUND ART
[0002] For the observation of tumors, there has been a method known
so far in the art, which makes use of a chemical compound that
tends to gather at cancer cells and emits fluorescence upon
irradiation with light (see Patent Publication 1). It is said there
that not only a fluorescent image but also a direct image is
simultaneously observable. Patent Publication 1 shows that the
wavelength characteristics of an illumination system and an
observation system overlap and are defined for the total
transmittance of the whole system.
[0003] In that case, reflection images of sites other than a
fluorescent site are observable through excitation light taken by
the overlap of both characteristics slightly in the observation
system.
[0004] Specifically, when 5-ALA (aminolevulinic acid) is used as
the fluorescent chemical, the excitation light wavelength is
.lamda..sub.e=about 410 nm and the fluorescence wavelength is
.lamda..sub.f=630 nm. The florescence wavelength is red and, to
observe this fluorescent site in good enough contrast, the
background color should preferably be blue, and close to a
monochrome. As the background color gets close to white, color
contrasts grow unacceptably low.
[0005] Patent Publication 1
[0006] Published Translation of PCT No. 11-511369
[0007] Thus, the florescence wavelength is red and when reflection
images of sites other than the fluorescent site are made observable
through light excitation light taken in the observation system,
there is the self-fluorescence of the living body to be observed
among factors affecting the background color. As an optical system
is designed without taking care of the self-fluorescence of the
living body, it gives rise to a drop of color contrasts. The
aforesaid prior art takes aim at making sure brightness contrasts:
it says nothing about details of color contrasts.
SUMMARY OF THE INVENTION
[0008] In view of such problems with the prior art as described
above, the object of the invention is to provide a biodiagnosis
apparatus in which the wavelength characteristics of an
illumination system and an observation system overlap to thereby
take excitation light in the observation system so that reflection
images of sites other than a fluorescent site are observable, and
which enables fluorescent observation to be implemented in good
enough color contrast.
[0009] According to one aspect of the invention by which the
aforesaid object is achieved, there is provided a bio-diagnosis
apparatus harnessing fluorescent reactions of a living body tissue,
which comprises a light source, a light source optical system, a
light transfer system for guiding illumination light from said
light source to the living body, an excitation light filter
interposed between said light source and said light transfer
system, an image transfer system for guiding light from the living
body to an image plane, and an excitation cut filter located in
said image transfer system, and in which spectral characteristics
of illumination light transmitting through said excitation light
filter and transmittance characteristics of said excitation cut
filter have an overlapping portion, characterized in that:
[0010] upon observation of a subject under said bio-diagnosis
apparatus, spectral characteristics of a site of the image plane
other than a fluorescent site satisfy the following condition
(1):
0.005.ltoreq.I(.lamda..sub.p+.DELTA.)/I(.lamda..sub.p).ltoreq.0.5
(1)
provided that 40.ltoreq..DELTA..ltoreq.80 nm, where .lamda..sub.p
is a wavelength (nm) at which spectral intensity reaches a maximum,
and I(.lamda..sub.p) is indicative of the then spectral
intensity.
[0011] According to another aspect of the invention, there is
provided a biodiagnosis apparatus harnessing fluorescent reactions
of a living body tissue, which comprises a light source, a light
source optical system, a light transfer system for guiding
illumination light from said light source to the living body, an
excitation light filter interposed between said light source and
said light transfer system, an image transfer system for guiding
light from the living body to an image plane, and an excitation cut
filter located in said image transfer system, and in which spectral
characteristics of illumination light transmitting through said
excitation light filter and transmittance characteristics of said
excitation cut filter have an overlapping portion, characterized in
that:
[0012] chromaticity coordinates (x, y) for light after transmitting
through said excitation cut filter satisfies the following
condition (2):
0.16.ltoreq.x.ltoreq.0.21, 0.04.ltoreq.y.ltoreq.0.23 (2)
[0013] According to yet another aspect of the invention, there is
provided a biodiagnosis apparatus harnessing fluorescent reactions
of a living body tissue, which comprises a light source, a light
source optical system, a light transfer system for guiding
illumination light from said light source to the living body, an
excitation light filter interposed between said light source and
said light transfer system, an image transfer system for guiding
light from the living body to an image plane, and an excitation cut
filter located in said image transfer system, and in which said
light source filter comprises a first transmissive area containing
a fluorescence excitation wavelength and a second transmissive
area, with transmittance characteristics of said excitation cut
filter including said second transmissive area of said light source
filter, characterized in that:
[0014] upon observation of a subject under said bio-diagnosis
apparatus, spectral characteristics of a site of the image plane
other than a fluorescent site satisfy the following condition
(1):
0.005.ltoreq.I(.lamda..sub.p+.DELTA.)/I(.lamda..sub.p).ltoreq.0.5
(1)
provided that 40.ltoreq..DELTA..ltoreq.80 nm, where .lamda..sub.p
is a wavelength (nm) at which spectral intensity reaches a maximum,
and I(.lamda..sub.p) is indicative of the then spectral
intensity.
[0015] In a preferable embodiment of the invention, said light
source comprises a first light source in alignment with said first
transmissive area and a second light source filter in alignment
with said second transmissive area, and is designed to direct
sequentially to the subject light transmitting through said first
light source filter and light transmitting through said second
light source filter.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1 is illustrative in schematic of the construction of
the biodiagnosis apparatus according to the invention.
[0017] FIG. 2 is illustrative of the transmittance characteristics
of the excitation light filter and excitation cut filter in a prior
art biodiagnosis apparatus.
[0018] FIG. 3 is illustrative of the system performance throughout
the conventional biodiagnosis apparatus.
[0019] FIG. 4 is indicative of the values, as calculated and found,
of the wavelength characteristics of the overlapping portion
(background site) of the wavelength characteristics of the
illumination system and the wavelength characteristics of the
observation system in the event that there are the system
performance of FIG. 3.
[0020] FIG. 5 is illustrative in schematic of the color contrasts
of the fluorescent and background sites in the even that 5-ALA is
used as a fluorescent chemical: (a) is indicative of a red
fluorescent site against a blue background, and (b) of a red
fluorescent site against a white background.
[0021] FIG. 6 is a spectral intensity distribution for the
background site at the upper limit, median and lower limit of the
overlapping amount of both characteristics of the illumination and
observation systems.
[0022] FIG. 7 is indicative of the system performance for obtaining
spectral characteristics at the upper limit, median and lower limit
of the FIG. 6, respectively.
[0023] FIG. 8 is a diagram wherein a spectral intensity
distribution for the background site at the upper limit, median and
lower limit of FIG. 6, respectively, is represented on a
chromaticity diagram.
[0024] FIG. 9 is indicative of the transmittance characteristics of
a light source filter in another example of the biodiagnosis
apparatus according to the invention.
[0025] FIG. 10 is indicative of the system performance throughout
the biodiagnosis system of the construction of FIG. 9.
[0026] FIG. 11 is indicative of the transmittance characteristics
in a modification to FIG. 9 wherein two light source filters are
used.
[0027] FIG. 12 is illustrative of an exemplary filter switchover
mechanism in the event that two light source filters are used as in
FIG. 11.
[0028] FIG. 13 is indicative of the transmittance characteristics
of an antireflection coat and an excitation light filter in an
optical system of the light source unit in the biodiagnosis
apparatus of FIG. 1.
[0029] FIG. 14 is indicative of the transmittance characteristics
of a prior art IR cut white light filter and an exclusive IR cut
filter located in a TV camera head in the biodiagnosis apparatus of
FIG. 15.
[0030] FIG. 15 is illustrative in schematic of an arrangement
wherein a TV camera system is connected to the biodiagnosis
apparatus of the invention for the purpose of taking images.
BEST MODE FOR CARRYING OUT THE INVENTION
[0031] The biodiagnosis apparatus of the invention is now explained
with reference to its principles and examples.
[0032] FIG. 1(a) is illustrative in schematic of the construction
of the biodiagnosis apparatus of the invention that comprises an
exclusive scope (endoscope) 1 capable of being inserted into, for
instance, the bladder and a light source unit 2 adapted to send
illumination light to an illumination system for the exclusive
scope 1 via a light guide cable 3. The light source unit 2
comprises a lamp 21 such as a xenon lamp, an optical system 22
adapted to condense light from the lamp 21 onto the input end of
the light guide cable 3, and a turret 23 located in an optical path
from the lamp 21. Around the turret 23, an excitation light filter
24, a white light filter 25, an IR cut white light filter 26 and an
emergency light (small electric bulb) 27 are selectively disposed,
as shown in FIG. 1(b). The excitation light filter 24 is one that
has such wavelength characteristics as described later and excites
fluorescent reactions; the white light filter 25 is one that
transmits light all over the wavelength range to observe an
ordinary image; the IR cut white light filter 26 is one that cuts
off wavelengths in the infrared range to observe an image with good
enough color reproducibility; and the emergency light (small
electric bulb) 27 is to make sure the minimum illumination light
for removing the exclusive scope 1 out of the living body when the
lamp 21 goes off. An optical path through the exclusive scope 1 is
provided in it with an excitation cut filter 11 so that an affected
site can be directly observed via an eyepiece unit 12, or it can be
observed via a CCD camera mounted to the eyepiece unit 12, as
described later.
[0033] First, problems with a conventional biodiagnosis apparatus
are explained. FIG. 2(a) is indicative of the transmittance
characteristics of the excitation light filter 24, and FIG. 2(b) is
indicative of the transmittance characteristics of the excitation
cut filter 11. The excitation light filter 24 and excitation cut
filter 11 have such transmittance characteristics; when the turret
23 is turned to insert the excitation light filter 24 in the
illumination light path, the whole bio-diagnosis system is going to
have such system characteristics as shown in FIG. 3, wherein the
wavelength characteristics (relative intensity) of an illumination
system overlap the wavelength transmittance of an observation
system near a wavelength of 440 nm, and fluorescence of a
fluorescent site excited by the excitation light of the
illumination system is going to occur near a wavelength of 630
nm.
[0034] As regards the system characteristics of FIG. 3, FIG. 4 is
indicative of the values of the wavelength characteristics, as
calculated and found, of a background site (with none of
fluorescent emission) that is defined by the overlap of the
wavelength characteristics of the illumination system with those of
the observation system. The calculated value here is the product of
the wavelength characteristics of the illumination system and the
wavelength transmittance of the observation system in FIG. 3, and
the found value is greater than the calculated value especially in
a wide range of wavelengths longer than the wavelength of 440 nm.
This portion of the background site greater than the calculated
value would appear to be caused by the self-fluorescence of the
living body. For this reason, if there is a background color
selected without taking care of this self-fluorescence of the
living body, it will then give rise to a drop of color contrasts
between the fluorescent site and the background site. This is the
problem with the biodiagnosis apparatus set forth in Patent
Publication 1.
[0035] As can be seen from the foregoing, the background color at
the time of fluorescent observations is determined by an excitation
light portion taken slightly in the observation system by the
overlap of the wavelength characteristics of the illumination
system and the observation system, and the self-fluorescence of the
living body under observation as well.
[0036] Here, the excitation light directed on the subject (an
affected site in the living body) stays constant, so is the
quantity of self-fluorescence emanating out of the living body. The
quantity of excitation light taken in the observation system is
determined by the amount of overlap of both characteristics of the
illumination system and the observation system: the ratio between
that quantity of excitation light and the quantity of
self-fluorescence is determined by the amount of overlap of both
characteristics of the illumination system and the observation
system. For this reason, the contrast of the background color,
i.e., the color contrast between the fluorescent site and the
background site is going to be determined by the amount of overlap
of both characteristics of the illumination system and the
observation system.
[0037] For observations in good enough contrasts, of importance is
the ratio between the excitation light taken in the observation
system and the self-fluorescence of the living body. As the amount
of overlap grows large, the self-fluorescence of the living body
becomes relatively smaller as compared with the excitation light
taken in: the background color gets close to a monochrome. As the
amount of overlap becomes small, on the contrary, the
self-fluorescence of the living body grows large with respect to
excitation light: the background color gets close to white.
[0038] FIG. 5 is illustrative in schematic of the color contrasts
between the fluorescent site and the background site in the event
that 5-ALA (aminolevulinic acid) is used as the fluorescent
chemical. When there is a red fluorescent site against a blue
background site, there is a good color contrast obtained so that
the fluorescent site (affected site) is easy to see, as can be seen
from FIG. 5(a). As there is a red fluorescent site against a white
background as shown in FIG. 5(b), on the contrary, there is no good
contrast obtained: the fluorescent site (affected site) is
difficult to see, resulting in an increased probability of
overlooking.
[0039] Therefore in the invention, the spectral characteristics of
the background site other than the fluorescent site on the image
plane upon observation of a subject should satisfy the following
condition:
0.005.ltoreq.I(.lamda..sub.p+.DELTA.)/I(.lamda..sub.p).ltoreq.0.5
(1)
provided that 40.ltoreq..DELTA..ltoreq.80 nm, where .lamda..sub.p
is the wavelength (nm) at which the spectral intensity reaches a
maximum, and I(.lamda..sub.p) is indicative of the then spectral
intensity.
[0040] As the upper limit of 0.5 to condition (1) is exceeded,
there is an increase in the proportion of the self-fluorescence of
the living body relative to the excitation light taken in by the
overlap of characteristics. As a result, the background color gets
close to white, giving rise to a drop of color contrasts, which may
otherwise make it difficult to see the fluorescent site (affected
site), resulting in an increased probability of overlooking.
[0041] As the lower limit of 0.005 to condition (1) is not reached,
on the other hand, there is a decrease in the proportion of the
self-fluorescence of the living body relative to the excitation
light taken in by the overlap of characteristics, because a lot
more excitation light is taken in the observation system. As a
result, there is light reflected off sites other than the
fluorescent site in addition to the fluorescence from the subject;
that is, the background becomes all too bright, giving rise to a
drop of brightness contrasts.
[0042] Especially when 5-ALA is used as the fluorescent chemical,
the excitation light wavelength is .lamda..sub.e=410 nm and the
fluorescence wavelength is .lamda..sub.f=630 nm. To observe orange
or red fluorescence in good enough contrasts, the background color
must tend to become a complementary color, or it should preferably
be blue.
[0043] FIG. 6 is indicative of the spectral intensity distributions
of the background site at the upper limit, median and lower limit
(corresponding to the upper limit, median and lower limit of
condition (1), respectively) of the amount of overlap of both
characteristics of the illumination system and the observation
system, and FIG. 7(a), 7(b) and 7(c) are indicative of the system
performances for obtaining the spectral characteristics at the
upper limit, median and lower limit of FIG. 6, respectively. In
FIG. 7 here, note that each solid line is indicative of the
wavelength characteristics (relative intensity) of the illumination
system, and each broken line is indicative of the wavelength
transmittance of the observation system.
[0044] The background at the lower limit of FIG. 6 (FIG. 7(c) is
whitish blue, the background at the median (FIG. 7(b)) is blue, and
the background at the upper limit (FIG. 7(a)) is deep blue.
[0045] The spectral intensity distributions of the background site
at the upper limit, median and lower limit (corresponding to the
lower limit, median and upper limit of condition (1), respectively)
of the amount of overlap of both characteristics of the
illumination system and the observation system in FIG. 6 may also
be expressed on a chromaticity diagram (CIE(X, Y)). On FIG. 8,
chromaticity coordinates (x, y) at the aforesaid upper limit,
median and lower limit are plotted. As can be appreciated from FIG.
8, it is desired that the chromaticity coordinates for light (on
the image plane) after transmitting through the excitation cut
filter 11 satisfies the following condition (2).
0.16.ltoreq.x.ltoreq.0.21, 0.04.ltoreq.y.ltoreq.0.23 (2)
[0046] The range of condition (2) is marked off by a broken line in
FIG. 8. Exceeding the upper limits of 0.21 and 0.23 to condition
(2) causes the background color to get to white, giving rise to a
drop of color contrasts between the fluorescent site and the
background site. This in turn makes it difficult to view the
fluorescent site (affected site), resulting in an increased
probability of overlooking. Falling short of the lower limits of
0.16 and 0.04 to condition (2) is not desirable because there is a
monochrome with an extremely noticeable blue tint. With visual
sensitivity in mind, the background gets dark, giving rise to
inconvenience that an image of light reflected off sites other than
the fluorescent site is hardly viewable, even when the energy of
the excitation light taken in the observation system is the
same.
[0047] To obtain an image of light reflected off sites other than
the fluorescent site in an image under observation, a light source
filter (located instead of the excitation light filter 24) disposed
in the illumination light path may be provided with a first
transmissive area and a second transmissive area, with such
transmittance characteristics as in FIG. 9. In this case, the first
transmissive area is designed to contain an excitation wavelength
for fluorescence (in the case of 5-ALA, the excitation light
wavelength is .lamda..sub.e=410 nm), and the second transmissive
area is designed to be contained in the transmissive are of the
excitation cut filter 11.
[0048] With the thus constructed arrangement, the whole
biodiagnosis system has such system performances as shown in FIG.
10, wherein light transmitting through the second transmissive area
is used to obtain a reflection image for the background other than
the fluorescent site.
[0049] In this case, too, it is desired that the spectral
characteristics of the background site other than the fluorescent
site on the image plane upon observation of the subject satisfies
the following condition (1):
0.005.ltoreq.I(.lamda..sub.p+.DELTA.)/I(.lamda..sub.p).ltoreq.0.5
(1)
provided that 40.ltoreq..DELTA..ltoreq.80 nm, where .lamda..sub.p
is the wavelength (nm) at which the spectral intensity reaches a
maximum, and I(.lamda..sub.p) is indicative of the then spectral
intensity.
[0050] As the upper limit of 0.5 to condition (1) is exceeded,
there is an increase in the proportion of the self-fluorescence of
the living body relative to the light passing through the second
transmissive area. As a result, the background color gets close to
white, giving rise to a drop of color contrasts, which may
otherwise make it difficult to see the fluorescent site (affected
site), resulting in an increased probability of overlooking.
[0051] As the lower limit of 0.005 to condition (1) is not reached,
on the other hand, there is a decrease in the proportion of the
self-fluorescence of the living body relative to the light
transmitting through the second transmissive area, because the
light transmitting through the second transmissive area enters more
the observation system. As a result, there is light reflected off
sites other than the fluorescent site in addition to the
fluorescence from the subject; that is, the background becomes all
too bright, giving rise to a drop of brightness contrasts.
[0052] It is noted that instead of providing the light source
filter disposed in the illumination light path with the first and
the second transmissive area, two light source filters may be used.
The first light source filter with such transmittance
characteristics as shown in FIG. 11 is designed to contain the
excitation wavelength for fluorescence as is the case with the
aforesaid first transmissive area, and the second light source
filter is designed to be contained in the transmissive area of the
excitation cut filter 11 as is the case with the aforesaid second
transmissive area.
[0053] Then, the light transmitting through the first light source
filter and the light transmitting through the second light source
filter are sequentially directed to the subject so that by making
use of the afterimage phenomenon of the observer's eye or field
sequential video image pickup, the fluorescent and background sites
can be superposed to implement observation in good enough color
contrasts. To direct sequentially to the subject the light
transmitting through the first light source filter and the light
transmitting through the second light source filter, such a turret
30 as shown in FIG. 12 is located. Around that turret 30 a first
light source filter 31 and a second light source filter 32 are
disposed in a continuously switchover way to turn that turret 30
continuously or reciprocally.
[0054] As a light source for the illumination light directed to the
subject, a laser that oscillates an excitation light wavelength may
be used instead of the light source filter having such
transmittance characteristics as shown in FIG. 9. Then, light of a
wavelength contained in the transmissive area of the excitation cut
filter 11 is superposed on the excitation light coming from that
laser, or directed sequentially to the subject in an alternate
manner.
[0055] Referring back to the biodiagnosis apparatus of FIG. 1(a),
the optical system 22 must not attenuate excitation light
transmitting through the excitation light filter 24; as can be seen
from the wavelength characteristics of FIG. 13, it is of importance
that an antireflection coating applied onto a lens, etc. in the
optical system 22 should have high transmittance with respect to
the wavelength transmitting through the excitation light filter
24.
[0056] FIG. 15(a) is illustrative in schematic of an arrangement
wherein a TV camera system is connected to the biodiagnosis
apparatus of FIG. 1(a) for imaging purposes. As is the case with
FIG. 1, the biodiagnosis apparatus itself comprises an exclusive
scope (endoscope) 1 capable of being inserted into, for instance,
the bladder, and a light source unit 2 for sending illumination
light to that exclusive scope 1 via a light guide cable 3. The
light source unit 2 comprises a lamp 21 such as a xenon lamp, an
optical system 22 adapted to condense light from the lamp 21 onto
the input end of the light guide cable 3, and a turret 23 located
in an optical path from the lamp 21. Around the turret 23, an
excitation light filter 24, a white light filter 25, a conventional
IR cut white light filter 26 and an emergency light (small electric
bulb) 27 are selectively disposed, as shown in FIG. 15(b). The
excitation light filter 24 is one that has such wavelength
characteristics as described above and transmits light containing
an excitation wavelength; the white light filter 25 is one that
transmits light all over the wavelength range to observe an
ordinary image; the conventional IR cut white light filter 26 is
one that cuts off wavelengths in the infrared range and transmits
light in the visible range to observe an image with good color
reproducibility, as can be seen from the transmittance
characteristics of FIG. 14 for conventional IR cutting; and the
emergency light (small electric bulb) 27 is to make sure the
minimum illumination light for pulling the exclusive scope 1 out of
the living body when the lamp 21 goes off. An optical path through
the exclusive scope 1 is provided in it with an excitation cut
filter 11 and an eyepiece unit 12 for the observation of an
affected site.
[0057] And, in the exemplary arrangement here, a TV camera head 40
is mounted on the eyepiece unit 12 of the bio-diagnosis apparatus
per se to enable a subject to be electronically imaged. The TV
camera head 40 has in it a CCD 41 and an exclusive IR cut filter 42
located on the entrance side of CCD 41. That exclusive IR cut
filter 42 is used instead of an absorption type IR cut filter such
as the conventional IR cut filter of FIG. 14 for the purpose of
keeping ordinary color reproducibility as conventional. To this
end, a filter with a cutoff frequency shifted to a longer
wavelength side is used in such a way as to have no influence on a
fluorescent image (fluorescent wavelength .lamda..sub.f=630
nm).
[0058] Video signals obtained from the TV camera head 40 are
forwarded to a camera control unit 43 to display and record taken
images, and feedback signals are forwarded from the camera control
unit 43 to the light source unit 2 for light control, etc.
[0059] While the biodiagnosis apparatus of the invention has been
described with reference to its principles and some specific
examples, it is to be understood that the invention may be modified
or changed in various ways.
INDUSTRIAL APPLICABILITY
[0060] The invention provides a biodiagnosis apparatus wherein the
wavelength characteristics of an illumination system and an
observation system overlap so that a reflection image other than at
a fluorescent site can be observed through excitation light taken
by that overlap in the observation system. The invention is
designed to satisfy condition (1) or (2) so that the fluorescent
site can be observed in good enough color contrasts against the
background.
* * * * *